Dominant Influence of Electron Inertia on Ion Cyclotron-Wave Generation in Plasma

Electron inertia is predicted to have a dominant influence on ion cyclotron-wave propagation as the wave frequency approaches the ion cyclotron frequency. This influence should effect a reduction in the Stix coil coupling to a plasma column as the plasma density is lowered. Experimental coupling measurements, taken over an appropriate range of plasma density (2×{}10¹⁰ to 2.8×{}10¹² cm^-3) on the Model-C stellarator, demonstrate the validity of the theoretical conclusion.